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<font size="4"><font face="monospace">BTW, I have found the
AdaptNull/SHARED_3 benchmark to extremely useful for detecting
*overall* regressions/improvements. (Obviously targeted
benchmarks are more useful for targeted problems like this one,
but if people are going to run one bench before and after a
change, it should be this one.)</font></font><br>
<br>
<div class="moz-cite-prefix">On 4/26/2023 11:12 AM, Adam Sotona
wrote:<br>
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<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US">FYI: Here is draft of pull request with initial
batch of performance improvements (no API change):<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US"><a href="https://github.com/openjdk/jdk/pull/13671" moz-do-not-send="true" class="moz-txt-link-freetext">https://github.com/openjdk/jdk/pull/13671</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US">It is branched from PR13478 due to its
significant changes in StackMapGenerator.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US">Here are some first measurable improvements:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US" lang="EN-US">Benchmark Mode Cnt
Score Error Units<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US" lang="EN-US">GenerateStackMaps.benchmark thrpt 10
407931.202 ± 13101.023 ops/s<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US">improved by approx 15% to:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US" lang="EN-US">GenerateStackMaps.benchmark thrpt 10
470826.720 ± 3569.194 ops/s<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US" lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Consolas;mso-fareast-language:EN-US" lang="EN-US">Adam<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<div style="border:none;border-top:solid #B5C4DF
1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">classfile-api-dev
<a class="moz-txt-link-rfc2396E" href="mailto:classfile-api-dev-retn@openjdk.org"><classfile-api-dev-retn@openjdk.org></a> on behalf of
Adam Sotona <a class="moz-txt-link-rfc2396E" href="mailto:adam.sotona@oracle.com"><adam.sotona@oracle.com></a><br>
<b>Date: </b>Tuesday, 25 April 2023 16:25<br>
<b>To: </b>Brian Goetz <a class="moz-txt-link-rfc2396E" href="mailto:brian.goetz@oracle.com"><brian.goetz@oracle.com></a>,
<a class="moz-txt-link-abbreviated" href="mailto:liangchenblue@gmail.com">liangchenblue@gmail.com</a> <a class="moz-txt-link-rfc2396E" href="mailto:liangchenblue@gmail.com"><liangchenblue@gmail.com></a>,
classfile-api-dev <a class="moz-txt-link-rfc2396E" href="mailto:classfile-api-dev@openjdk.org"><classfile-api-dev@openjdk.org></a><br>
<b>Subject: </b>Re: Caching symbolic descriptors for the
constant pool<o:p></o:p></span></p>
</div>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US">I think it perfectly fits to the performance
improvements I’m working on.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US">The “caching” here means to 1:1 store symbol
with PoolEntry after the first request or when the entry has
been created from the symbol.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US">There is no risk of any growing global caches.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US">If the Constants API will also “cache” internal
class name in ClassDesc and ClassDescs of the MethodTypeDesc
parameters and return type.
</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US">Then we can achieve paths with minimal or no
conversions, for example:</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US" lang="EN-US">ClassDesc -> MethodTypeDesc ->
CodeBuilder -> PoolEntry -> InvokeInstruction ->
StackMapGenerator -> ClassHierarchyResolver ->
ClassDesc -> internal class name ->
StackMapGenerator.Type -> PoolEntry -> BufWriterImpl
-> internal class name</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US"> </span><o:p></o:p></p>
<div style="border:none;border-top:solid #B5C4DF
1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">classfile-api-dev
<a class="moz-txt-link-rfc2396E" href="mailto:classfile-api-dev-retn@openjdk.org"><classfile-api-dev-retn@openjdk.org></a> on behalf of
Brian Goetz <a class="moz-txt-link-rfc2396E" href="mailto:brian.goetz@oracle.com"><brian.goetz@oracle.com></a><br>
<b>Date: </b>Tuesday, 25 April 2023 16:12<br>
<b>To: </b><a class="moz-txt-link-abbreviated" href="mailto:liangchenblue@gmail.com">liangchenblue@gmail.com</a>
<a class="moz-txt-link-rfc2396E" href="mailto:liangchenblue@gmail.com"><liangchenblue@gmail.com></a>, classfile-api-dev
<a class="moz-txt-link-rfc2396E" href="mailto:classfile-api-dev@openjdk.org"><classfile-api-dev@openjdk.org></a><br>
<b>Subject: </b>Re: Caching symbolic descriptors for the
constant pool</span><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:11.0pt">For caching symbols in the Class
API, this is fine but we should wait a
<br>
bit. Doing caching raises the question of where the cache
lives and how <br>
long it lives; we had some discussions recently about
caching for class <br>
hierarchy info, and concluded that we had reached the
limits of what we <br>
can do with static entry points. By refactoring the main
entry points <br>
(build/parse) to instance methods on a user-controlled
"classfile <br>
context" object, we create a logical place and lifetime
for caches, of <br>
which we now have two examples.<br>
<br>
Adam currently has a queue of patches he is trying to
shepherd in, after <br>
which we will look at refactoring the CHA functionality,
after which we <br>
will look at refactoring the "front door", and then that
should leave a <br>
natural place to slot in caching of symbolic constants.<br>
<br>
On 4/24/2023 7:18 PM, - wrote:<br>
> First, thanks for the feedback on my cache proposal a
few days ago!<br>
> I've prepared two patches under 8306697<br>
> <a href="https://github.com/openjdk/jdk/pull/13598and" moz-do-not-send="true" class="moz-txt-link-freetext">https://github.com/openjdk/jdk/pull/13598and</a>
8306698<br>
> <a href="https://github.com/openjdk/jdk/pull/13599" moz-do-not-send="true" class="moz-txt-link-freetext">https://github.com/openjdk/jdk/pull/13599</a>,
which will hopefully make<br>
> the Constant API more useful with classfiles.<br>
><br>
> I wish to cache symbolic descriptors in classfile API
itself. One of<br>
> the prime candidates identified by Adam in his
migration of<br>
> java.lang.invoke to classfile API is
ClassEntry.asSymbol, which from<br>
> my search, appears to be frequently used in stack map
generation. In<br>
> addition, a MethodTypeDesc is passed to stack map
generator<br>
> constructor via ofDescriptor (which has slow parsing
even after Adam's<br>
> optimization), but the parsing can totally be averted
if we can reuse<br>
> the MethodTypeDesc passed in withMethod(). Thus, I
wish to add<br>
> accessors like typeSymbol() and cachedTypeSymbol()
for MethodInfo to<br>
> speed up StackMapGenerator initialization.<br>
><br>
> In addition, the stack map generator has a custom
bitset-based tool to<br>
> split a descriptor on the fly (See<br>
> StackMapGenerator.processInvokeInstructions). I
believe they can<br>
> benefit from reusing a parsed MethodTypeDesc as well,
especially if<br>
> the invoke instructions were originally built with
MethodTypeDesc.<br>
><br>
> Chen Liang</span><o:p></o:p></p>
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